Calcium-aluminum-rich inclusions (CAIs) are millimeter-sized refractory
objects found in primitive meteorites. CAIs are considered as some of the first
solids to form in the solar system, because they are refractory.
FUN CAIs, those with Fractionated and Unknown Nuclear effects,
are a small subset of CAIs. These FUN CAIs show correlated excesses and
deficits in the neutron-rich iron-group isotopes such as $\ca{48}$ and
$\ti{50}$ which regular CAIs do not. Interestingly, these isotopes are most 
likely produced infrequently
but in huge quantities in a rare class of thermonuclear (Type Ia) supernovae. 
I propose
that the isotopic effects in the neutron-rich iron-group nuclei in FUN CAIs
arise from the rarity of the Type Ia supernovae that produce them. To 
quantitatively test this hypothesis we built a simple Ia model to get
the yields, and then estimated the chemical forms and sizes of dust grains
into which those
isotopes condense. Our results show that these rare dense Type Ia supernovae
can produce a large quantity of neutron-rich iron-group isotopes and the dust
size is in the order of 0.1 micron. 
The future Galactic Chemical Evolution simulation with these inputs would
help constrain the Solar System formation in the nucleosynthetic and dust
formation aspects. 

